class ProtocHead:
    '''
    协议头:
        byte[],共48字节
    '''
    def __init__(self):
        self.packLength = None
        self.cmd = None
        self.senderId = None
        self.clientOs = None
        self.version = None
        self.result = None
        self.time = None
        self.receiverId = None
        self.traceId = None
        self.ack = None
